Please help me with details on how to design a simple incinirator. A design example will sufice.

Hello Galadima

What type of incinerator are you looking for?
What capacity do you need?
What temperature are you looking for?
What energy source do you intend to use?
What do you need to incinerate? A single sheet of paper, several wet towels, or some nasty family member? :)
What about your contribution to a better environment? You really want a polluting incinerator in the backyard?